Brake disk and brake with integral thermal fuse

Abstract

A brake disk defines an annular shape having a radially inner side and a radially outer side. The brake disk includes: a radially outer braking surface, the braking surface having a maximum operating temperature; a fusible material section radially inward from and connected to the braking surface. The fusible material has a maximum operating temperature, the fusible material section suitable for transmitting torque between the braking surface and a shaft. The maximum operating temperature of the braking surface is higher than the maximum operating temperature of the fusible material section. When the temperature of the fusible material section raises above the maximum operating temperature of the fusible material section, the fusible material section is configured to no longer transmit torque between the braking surface and the shaft.

The invention claimed is: 
     
       1. A brake disk, the brake disk defining an annular shape having a radially inner side and a radially outer side; the brake disk comprising:
 a radially outer braking surface, the braking surface having a maximum operating temperature; 
 a fusible material section radially inward from and connected to the braking surface, the fusible material having a maximum operating temperature, the fusible material section for transmitting torque between the braking surface and a shaft while a temperature of the fusible material section is below the maximum operating temperature of the fusible material section; 
 wherein the maximum operating temperature of the braking surface is higher than the maximum operating temperature of the fusible material section; and 
 wherein when the temperature of the fusible material section raises above the maximum operating temperature of the fusible material section, the fusible material section is configured to no longer transmit torque between the braking surface and the shaft; and 
 wherein the fusible material section comprises a spline extending circumferentially around a radially outer side of the fusible material section; and/or wherein the fusible material section comprises a spline extending circumferentially around a radially inner side of the fusible material section. 
 
     
     
       2. The brake disk of  claim 1 , further comprising an annular mounting portion, wherein one or more teeth are formed in a radially innermost surface of the mounting portion. 
     
     
       3. The brake disk of  claim 2 , wherein the annular mounting portion comprises a first portion and a second portion, wherein the fusible material section is formed between the first and second portions of the mounting portion, such that the fusible material section is connected to the braking surface via the second portion of the mounting portion. 
     
     
       4. The brake disk of  claim 2 , wherein the mounting portion has a first axial thickness, wherein the fusible material has a second axial thickness, and wherein the braking surface has a third axial thickness, wherein the third axial thickness is less than the first and second axial thicknesses. 
     
     
       5. A brake for an aircraft comprising:
 a housing; 
 a shaft defining an axis (X) and extending into the housing and having teeth or splines; 
 a first brake pad and a second brake pad; and 
 the brake disk of  claim 1  arranged on or formed integrally with the shaft and located axially between the first and second brake pads; 
 wherein the brake is configured to move at least one of the brake pads to press against the braking surface of the brake disk to resist rotation of the brake disk via friction and thereby resist rotation of the shaft. 
 
     
     
       6. The brake of  claim 5 , wherein the fusible material section has a minimum thickness (A) in the radial direction, and wherein a gap having a length (B) is defined between a radially outermost surface of the braking disk and an inner surface of the housing, wherein the minimum thickness (A) is larger than the gap length (B). 
     
     
       7. The brake of  claim 5 , further comprising one or more bearings mounted to the shaft and to the housing for supporting the shaft for rotation within the housing, and/or further comprising an actuator for moving one of the first or second brake pads axially within the housing along the direction of the shaft axis (X). 
     
     
       8. The brake disk of  claim 1 , wherein the fusible material section has a non-circular profile at a radially outer surface; or wherein the fusible material section has a non-circular profile at a radially inner surface. 
     
     
       9. The brake disk of  claim 8 , wherein each non-circular profile comprises one of: a toothed outer-profile, a splined outer profile, and a zig-zag outer profile. 
     
     
       10. The brake disk of  claim 1 , wherein the fusible material section is made from a eutectic material. 
     
     
       11. The brake disk of  claim 1 , wherein one or more teeth are formed at a radially innermost surface of the fusible material section. 
     
     
       12. The brake disk of  claim 1 , wherein the maximum operating temperature of the fusible material section is within the range of 200° C. to 1000° C.; or wherein the fusible material section is configured to melt, to thermally decompose, or to substantially weaken when above its maximum operating temperature, so as to no longer transmit torque to the braking surface. 
     
     
       13. A method of making a brake disk, the method comprising:
 pouring a molten fusible material into an annular gap between two components, wherein the two components are either: 
 1) First and second mounting portions of the brake disk; or 
 2) a mounting portion and a braking surface of the brake disk; or 
 3) a braking surface of the brake disk and a sacrificial component; or 
 9) A braking surface of the disk brake and a shaft; 
 the method further comprising: 
 solidifying the fusible material to form a fusible material section between the first and second components; 
 wherein the fusible material section comprises a spline extending circumferentially around a radially outer side of the fusible material section; and/or wherein the fusible material section comprises a spline extending circumferentially around a radially inner side of the fusible material section. 
 
     
     
       14. The method of  claim 13 , further comprising machining an annular groove into one or both of the components, such that when the molten fusible material is poured into the annular gap, the molten fusible material fills the groove(s).